Kodak Files Patent for Edible RFID Tag

NewScientist.com has uncovered a recently filed patent application from camera and imaging technology giant Kodak that outlines a compelling new application of RFID: ingestible tags that act as monitors for health characteristics within the human body.

February 14, 2007—NewScientist.com has uncovered a recently filed patent application from camera and imaging technology giant Kodak that outlines a compelling new application of RFID: ingestible tags that act as monitors for health characteristics within the human body.

The idea is that the RFID tag antenna -- the critical component which allows data to broadcast -- be composed of organic material that would dissolve as a result of certain chemical reactions within the human body. Once dissolved, the tag antenna, and therefore the tag itself, would stop transmitting a signal, indicating that the targeted chemical reaction had occurred. Kodak calls them "fragile tags":

This invention is a system that uses intentionally fragile tags to provide useful information by identifying when such tags are destroyed. The system then responds to this basic change of state by providing a useful service. Such intentionally fragile tags can be composed of materials that can be not only be ingested but also digested with the understanding that breakdown is a desirable quality and one that enables the tag materials to be eliminated in the standard manner. Such a fragile tag that is also digestible lends itself to applications such as being included in objects meant to be ingested, such as pills, lozenges, and glycol strips.

For example, imagine an RFID reader-equipped drug dispenser installed in the home bathroom of a patient. The patient is prescribed to take a pill every day, which is issued by the dispenser. Once the pill is issued, the dispenser's RFID reader activates and begins polling for the signal of a Kodak tag, which is physically attached to the dispensed pill. In this uningested state, the tag functions properly, responding to the RFID reader's interrogation, which in turn informs the dispenser that the day's dosage has not yet been taken. Once the patient ingests the pill/tag, the organic tag antenna is subjected to chemicals within the patient's stomach. The tag antenna was designed to rapidly dissolve in the presence of normal stomach chemicals, so after only a few minutes it does so, and the tag ceases to respond to the RFID reader signal, which the dispenser interprets as the patient having taken her daily medication.

The concept could be applied to changes in mechanical states as well. "In another application," reads the patent, "the fragile tag is engineered to breakdown under mechanical stresses rather than by chemical reaction. Such a tag may be affixed to an artificial, or natural body part. It is then implanted and can be remotely queried. When wear on the body part, for example, an artificial hip, has proceeded to a predetermined level, the tag is rendered useless thus alerting the remote query that the body part has achieved an unsatisfactory level of wear."

The patent notes that in addition to passive, active RFID technology could be used instead, depending on the application. It also notes the possibility of using multiple tags in parallel to gather more nuanced data about an environment based on an assessment of which tags are destroyed and which survive: "Another embodiment uses multiple tags whose packaging yields useful information from some combination of the tags being destroyed or surviving conditions, such as when compounds in the stomach destroy some tags but leave others."

What makes the Kodak invention notable is not just the novel applications; it is the ability to turn pure RFID into a sort of sensor. It has been long predicted that RFID and sensors would be combined, whereby a sensor gathers environmental information that is stored on an accompanying RFID tag. Indeed, this technology architecture is already seeing adoption in numerous areas, like the cold chain.

The Kodak concept is different in that it incorporates environmental sensing as an intrinsic part of the RFID tag itself, so that the tag becomes a sort of threshold-meter, causing an alert when the tracked environmental characteristic passes a certain point. It is a clever, elegant concept that might open the door to many applications where a tag-sensor hybrid device is undesirable because of size, cost, or complexity.